The invention relates to a spindle or worm drive for adjustment devices in motor vehicles, more particularly for seat adjustment devices, window lifters and sliding roofs.
From DE 198 61 100 A1 a spindle drive is known for adjustment devices in motor vehicles having a fixed spindle which is fixed on a first of two relatively rotatable parts, a gearing mechanism which is mounted on the second of the relatively rotatable parts, and a gear housing for accommodating the gearing. The gear housing consists of two housing plates which are fixed against each other by means of push-fit connections and which are designed as supporting connecting points where the housing plates are held together and which take up the gear forces. The push-fit connections have raised zones and recesses which fit into each other and initially form a play-fit. The housing plates are fixed by plastically deforming the material in the region of the push-fit connections.
From U.S. Pat. No. 4,802,374 a spindle drive is known for a seat longitudinal adjuster in motor vehicles which contains a spindle which is connected to the adjusting rail of the seat longitudinal adjuster and which can be driven through an electric motor by a spindle nut, worm wheel and a worm connected to a motor shaft. The worm, the worm wheel and the spindle nut are mounted in a retaining clip having two cylindrical sleeves which intersect at right angles. A retaining flange which is connected to the base rail of the seat longitudinal adjuster and consists of a clip with a rectangular window-shaped opening surrounds the cylindrical sleeves of the retaining clip through the frame of the window-shaped opening, and thus secures the position of the retaining clip.
With this spindle drive which is known from U.S. Pat. No. 4,802,374 the tolerances of the individual component parts determine the overall play of the spindle drive so that to reduce the clearance of the spindle drive narrow tolerances have to be set which requires considerable manufacturing expense.
A further drawback of the known spindle drives is that the retaining flange does indeed secure the position of the retaining clip but offers no security in the event of a crash since the retaining flange only surrounds a part of the retaining clip and in the event of a crash is bent so that the coupling between the movable adjusting rail and the base rail fixed on the body is released and thus a vehicle seat connected to the adjusting rail will move uncontrollably.
The object of the present invention is therefore to provide a spindle or worm drive for adjustment devices in motor vehicles of the type already described which guarantees a play-free bearing of the gear elements protected against dirt, a crash-safe connection of the gearing mechanism and thus of the adjustment device as well as a bearing of the gearing mechanism which is able to pivot when necessary about at least one axis.